1. Field of the Invention:
The present invention relates generally to an ultrasonic machining technique, and more particularly to a spindle and a flexible hinge used in an ultrasonic machine.
2. Description of Related Art:
Since it is quite difficult to machine brittle materials such as semiconductors, ceramics, glass or hard alloys through conventional machining techniques using mechanical and thermal energies, there have been developed new machining techniques using such as electric, magnetic, optical, or chemical energies. Ultrasonic machining technique is such an assisting machining technique.
Ultrasonic machining technique applies ultrasonic energy to such as cutting work, wherein vibration in an axial direction generated by an ultrasonic vibrating unit mounted to a rear end of a spindle is transmitted through the spindle and the base of a cutting tool and reaches outer periphery of the cutting tool and is converted to movement in the axial direction. Through the vibration conversion, a desired vibration way needed by the ultrasonic machining can be achieved. Meanwhile, by choosing suitable cutting tools, various types of machining can be performed, such as forming sketched holes, engraving or cutting-off. The ultrasonic machining technique can be performed regardless of whether the workpiece is a conductor or not and particularly suitable to be applied in precision machining of brittle materials. Related techniques are disclosed in such as US Pat. Nos. 6,762,535 and 7,175,506 etc.
US Pat. No. 6,762,535 discloses a spindle structure used in an ultrasonic machine and a supporting born used in the same, wherein, the spindle structure comprises a spindle main body having a main body sleeve, an ultrasonic vibrator housed in the main body sleeve, and a supporting born connected to the ultrasonic vibrator. The supporting born comprises a main body, a base portion formed in a brim shape on an outer peripheral face of the main body, a damping sleeve formed by extending the brim-shaped base portion in an axial direction, a loose flange and a fixing flange respectively formed on both ends of the damping sleeve, and a buffer groove formed on an outer peripheral face of the base portion. The loose flange is disposed on the side of the ultrasonic vibrator in a state that it is slidable to and has contact with an inner peripheral face of the main body sleeve, and the fixing flange is restrained in the axial direction. The supporting horn is housed in the main body sleeve.
However, the ultrasonic vibrator disclosed by US Pat. No. 6,762,535 does not have pre-pressure and is only connected to the supporting born functioning as a medium and not directly connected to the rotor. Meanwhile, length of the ultrasonic vibrator is preferable to be set to ½ of the wavelength of an ultrasonic wave. That is, the design of the supporting horn is rather complicated. Also, this prior art uses the loose flange to guide vibration of a working tool in an axial direction and strengthen radial rigidity of the working tool.
US Pat. No. 7,175,506 discloses a tool unit for the ultrasonically assisted rotary machining of a workpiece. The tool unit is applied in a spindle of a machine comprising a retainer. The tool unit comprises a holder at least partially insertable in the retainer, a converter disposed inside the holder, and an electroacoustic transducer disposed inside the converter for generating and transmitting ultrasonic vibration, the holder can be detachably connected to the retainer.
However, the ultrasonic vibrator disclosed by US Pat. No. 7,175,506 also does not have pre-pressure and is only connected to the converter functioning as a medium and not directly connected to the rotor. Meanwhile, length of the ultrasonic vibrator is preferable to be set to ½ of the wavelength of an ultrasonic wave. That is, the design of the converter is rather complicated. Also, this prior art uses a seal ring to guide vibration of a working tool in an axial direction and strengthen radial rigidity of the working tool.
Therefore, there is a need to develop a technique capable of overcoming the above-described drawbacks.